Extension dog system for veneer slicer

ABSTRACT

A veneer slicer comprising a flitch table providing a mounting surface, dogs for gripping a flitch at a first distance from the mounting surface, and a knife and pressure bar assembly movable along a path toward and away from the mounting surface, the flitch table being reciprocable between first and second opposite positions transversely relative to the path of the knife and pressure bar assembly. Extension dog assemblies are mounted on the flitch table and proportioned and designed to grip a flitch at a second and greater distance from the mounting surface, each extension dog assembly including opposing jaws positioned and designed to engage generally opposite portions of a flitch, means for guiding the jaws for movement toward the central portion of a mounting surface to their gripping positions and away from the central portion to their releasing positions, and power means for moving the opposing jaws between their respective gripping and releasing positions. The guiding means and power means are proportioned and designed such that, when the flitch table reciprocates between its opposite positions and the jaws are in their respective releasing positions, the jaws will not interfere with the knife and pressure bar assembly when it moves toward the mounting surface with the space defined by the said second distance.

United States Patent Hale [ 1 'Aug. 1,1972

[54] EXTENSION DOG SYSTEM FOR VENEER SLICER [72] Inventor: Thomas F. Hale, New Albany, Ind.

[73] Assignee: Capital Machine Company, Inc., In-

dianapolis, Ind.

[22] Filed: March 17, 1971 [21] Appl. No.: 125,064

[52] US. Cl ..144/l78, 143/125 A [51] Int. Cl. ..B27l 5/06 [58] Field of Search..l43/l25, 125 A, 126, 127, 128,

Primary Examiner-Donald R. Schran Attorney-Hood, Gust, Irish, Lundy & Coffey 5 7 ABSTRACT A veneer slicer comprising a flitch table providing a mounting surface, dogs for gripping a flitch at a first distance from the mounting surface, and a knife and pressure bar assembly movable along a path toward and away from the mounting surface, the flitch table being reciprocablc between first and second opposite positions transversely relative to the path of the knife and pressure bar assembly. Extension dog assemblies are mounted on the flitch table and proportioned and designed to grip a flitch at a second and greater distance from the mounting surface, each extension dog assembly including opposing jaws positioned and designed to engage generally opposite portions of a flitch, means for guiding the jaws for movement toward the central portion of a mounting surface to their gripping positions and away from the central portion to their releasing positions, and power means for moving the opposing jaws between their respective gripping and releasing positions. The guiding means and power means are proportioned and designed such that, when the flitch table reciprocates between its opposite positions and the jaws are in their respective releasing positions, the jaws will not interfere with the knife and pressure bar assemblyvwhen it moves toward the mounting surface with the space defined by the said second distance.

11 Claims, 4 Drawing Figures PAIENTEmuc' 1 m2 sum 1 OF 2 INVENTOR THOMAS F. HALE EXTENSION DOG SYSTEM FOR VENEER SLICER It is a primary object of my present invention to provide, for use on a conventional veneer slicer, a plurality of extension dog assemblies mounted on the flitch table of the slicer and proportioned and designed to grip a flitch at a greater distance from the mounting surface of the flitch table than the gripping distance of the dogs conventionally provided on the flitch table. My extension dog assemblies include opposing jaws positioned and designed to engage generally opposite portions of a flitch, means for guiding the jaws for movement toward the central portion of the flitch table to their gripping positions and away from the central portion to their releasing positions, and power means for moving the opposing jaws between their respective gripping and releasing positions. The guiding means and power means of my extension dog assemblies are proportioned and designed such that, when the flitch table reciprocates between its opposite positions and the jaws of the extension dog assemblies are in their respective releasing positions, the jaws will not interfere with the knife and pressure bar assembly when it moves toward the mounting surface of the flitch table and within the space defined by the jaws when they are in their gripping positions.

My extension dog assemblies are constructed so that their jaws can be moved from their gripping positions to their releasing positions during the slicing operation merely by operating a valve and without disturbing or halting the slicing operation.

Further, my extension dog assemblies are laterally narrow assemblies which can be inserted into laterally narrow spaces between the conventional dogs on a flitch table, each assembly including a vertically elongated rigid frame which is rigidly connected to the flitch table and the vertically extending members of which provide means for guiding the opposing jaws of my extension dog assemblies.

Other objects and features of my present invention will become apparent as this description progresses.

To the accomplishment of the above and related objects, my invention may be embodied in the form illustrated in the accompanying drawings, attention being called to the fact, however, that the drawings are illustrative only, and that change may be made in the specific construction illustrated and described, so long as the scope of the appended claims is not violated.

In the drawings:

FIG. 1 is a fragmentary elevational view of a veneer slicer on which my extending dog assemblies are mounted;

FIG. 2 is a fragmentary perspective view of a portion of the flitch table of the slicer of FIG. 1;

FIG. 3 is an enlarged fragmentary sectional view showing the opposing jaws of one extension dog assembly and the means by which the opposing jaws are guided for movement between their gripping positions and releasing positions; and

Flg. 4 is a fragmentary enlarged sectional view showing my preferred power means for moving the jaws shown in FIG. 3.

Referring now to the drawings, and particularly to FIGS. 1 and 2, it will be seen that I have illustrated a veneer slicer of conventional form comprising a base 12, flitch table supports 14 (only one of which is shown in the drawings), and a flitch table 16. This type of flitch table 16 and the means by which it is supported for reciprocation is well known and was disclosed as early as June 27, 1905 in US. Pat. No. 793,306 issued to Louis Koss. Particularly, the plurality of transversely spaced apart supports 14 provide guides such as indicated at 18 upon which the flitch table 16 reciprocates as indicated by the arrow 20 in FIG. 2. For reasons which are well known in the veneer slicing art, the table 16 reciprocates in a generally vertical plane, but the reciprocation is along a line inclined with respect to vertical.

Conventionally, a plurality of transversely spaced apart dogs 30, 32 for gripping a flitch 33 at relatively short distances from the mounting surface of the flitch table 16 and holding the flitch rigidly against a central portion of the mounting surface is provided. In the illustrated conventional system, the lower dogs 30 and the upper dogs 32 are guided for vertical reciprocation on the flitch table 16 anddriven by hydraulic cylinders 34, 36, respectively. Conventionally, a flitch 33 is held against the central portion of the mounting surface of the flitch table 16 to extend longitudinally therealong and the lower dogs 30 are driven upwardly and the upper dogs 32 are driven downwardly to engage the flitch at a point approximately five-eighths inch from the mounting surface to hold the flitch rigidly against the mounting surface. The hydraulic cylinders 34, 36, and their respective piston rods 35, 37 are effective to drive the teeth potion 38 of the dogs 30, 32 into the flitch 33, the teeth portions being proportioned and designed to wedge the back surface of the flitch tightly against the mounting surface of the flitch table 16.

The slicer 10 includes a carriage 42 mounted on the base 12 for guided shiftable movement toward and away from the plane of reciprocation of the flitch table 16 as indicated by the arrow 44. The means by which the carriage 42 is shifted in the direction of the arrow 44 is well known and conventional. A knife and pressure bar assembly, indicated generally by the reference numeral 46, is mounted on the carriage 42 so that the assembly is movable along a path toward and away from the mounting surface of the flitch table 16. In the illustrated slicer 10, a member 48 (commonly called a skirt) is provided for supporting the knife 50 at a point just below the pressure bar 52, the pressure bar 52 being carried by an assembly 54 (commonly called a cap) which is adjustably movable on the skirt 48. This arrangement of a knife 50, pressure bar 52, skirt 48, a cap 54 are well known and disclosed, for instance in the early Koss US. Pat. No. 793,306 issued June 27, 1905 and a later Koss US. Pat. No. 3,441,069 issued Apr. 29, 1969.

From the description thus far, it will be appreciated that the flitch table 16 reciprocates transversely in a generally vertical plane relative to the path of the knife and pressure bar assembly 46 and between first and second opposite positions, i.e., its upper and lower positions. The knife 50 and pressure bar 52 move inwardly toward the flitch table 16 and the flitch 33 carried thereon. As the flitch 33 moves downwardly, the knife and pressure bar assembly 46 slices a thin sheet of veneer from the flitch. The assembly 46 is advanced step-by-step toward the flitch table 16, the distance of each step being approximately equal to the thickness of the slice of veneer being cut and each step being completed before the table l6 begins to move downwardly. Means, not shown, are provided for tilting the assembly 46 rearwardly to permit the table 16 and the flitch 33 to move to its upper position from its lower position.

Conventionally, during the slicing operation, the assembly 46, i.e., the cutting edge of the knife 50 and the contacting edge of the pressure bar 52 move toward the flitch'table 16 to the point where the assembly is just to the left (FIG. 1) of the plane defined by the movement of the dogs 30, 32. Of course, further movement of the assembly 46 to the right (FIG. 1) will bring the knife 50 and pressure bar 52 into contact withthe reciprocating dogs 30, 32, thereby damaging the knife 50, pressure bar 52, and dogs 30, 32.

Thus, the portion of the flitch to the right (FIG. 1) of the plane defined by the dogs 30, 32, i.e., the portion of the flitch engaged by the dogs30, 32, conventionally cannot be sliced into veneer. For this reason, the distance from the mounting surface of table 16 at which the dogs 30, 32 engage the flitch 33 is kept at an absolute minimum because this distance establishes the amount of valuable flitch which cannot be sliced into veneer. a

Often it is desirable to slice flitches which are extremely large and which are not so easily clamped by the conventional dogs 30, 32. which are spaced so closely to the mounting surface of the flitch table 16. In other words, the conventionally spaced dogs 30, 32 often will not engage and grip asufiicient portion of a rather large flitch securely to fasten it to the flitch table 16. Further, sometimes it is advantageous to slice a log which has not been split longitudinally to provide the relatively large flat bearing surface provided by the flitch 33. in FIG. 1. In such a case,the log is usually cut to provide only a relatively small flat longitudinally extending surface which is placed against the mounting surface of the table 16. When the dogs 30, 32 engage sliced down to the plane at which the flitch is glued to the backing board. This procedure, of course, results in a greater number of veneer slices from a flitch because the glue plane between the flitch and the backing board is disposed to the left (FIG. 1) of the vertical plane in which the dogs 30, 32 reciprocate. This concept of gluing flitches to backing members and then slicing down to the glue plane is disclosed in US. Pat. No. 3,295,571

issued Jan. 3, 1967 to Per Bork and in a subsequent US. Pat. No.'3,397,723 isSued Aug. 20, l968 to David E. Hervey.

One of the problems with the gluing operation just described is that the person operating theveneer slicer is often concerned about whether or not the glue joint will hold during the slicing operation, especially when rather large flitches are glued to backing boards which are clamped to the flitch table. If the glue joint fails, the

flitch could fall from the flitch table and damage the veneer slicer. My invention facilitates the slicing of large flitches, whole logs which have not been cut to provide a large flat bearing surface and flitches which have been glued to backingboards.

My invention, therefore,-comprises extension dog assemblies mounted on the flitch table and proportioned and designed to grip a flitch at a distance from the mounting surface of the flitch table 16 greater than the gripping distance of the conventional dogs 30, 32, the

extension dog assembliesbeing retractable to a position such that they will not cross the path of the knife and pressure bar assembly 46 5 when the table I6 reciprocates.

My extension dog assemblies, one such assembly j i being indicated'generally by the reference numeral 60 in the drawings, are proportioned and designed to be incorporated on flitch tables of veneerslicers of the type described above. The number of extension dog assemblies 60 utilized on a slicer will 'depend .on the length of the slicer, i.e., the length offlitches which can be cut in the slicer. Further, 'my extension dog assemblies 60 are laterally narrow assemblies which can be inserted into laterally narrow spaces on the flitch table 16, each assembly including a frame portion which is connected to the flitch table.

Each extension dog assembly 60includes opposing jaws 62, 64, power means 66 and guide means 68 for the jaws. The jaw 62 is the upper jaw and the jaw 64 is the lower jaw in the illustrative embodiment, the power means 66 including a hydraulic cylinder drive for the lower jaw and a hydraulic cylinder drive for the upper jaw as will be explained hereinafter.

The guide means 68 is provided by the main support frame of the assembly 60, this frame including laterally spaced apart and vertically extending guide and frame members 70, 72, which are rigidly connected together, for instance, by a cross bar 74 at their. tops and cross bars 76 at their backs. The power means 66 is mounted on the cross bar 74-as best seen in FIG. 4. The cross bar I 74 may be provided with openingssuch as indicated at through which fastening elements extend to engage, respectively, guide and frame members 70, 72; The frame assembly just described may be rigidly attached to the flitch table 16 by means such as the illustrated fastening elements 78 which extend through the cross bars 76.

The inwardly facing surfaces of the members 70, 72, are provided with allochirally arranged longitudinally extending grooves 80 having lower cured portions 82 and upper curved portions 84, the groove 80in the member 70 being shown in FIG. 3. The function of these grooves 80 is to provide guides or ways for rollers, as will be more fully explained hereinafter.

The upper jaw 62 includes a pair of laterally spaced apart arm members 90, 92 which may be rigidly fastened together by means such as the illustrated back brace 94 (FIG. 3) and fastening elements 96 and by the illustrated front braces 98, 100 to which the blade 102 is connected by means such as the illustrated fastening element 104. It will be appreciated that the arm members 90, 92 and, for instance, the brace member 100 may be integrally formed such as by casting processes. The blade 102 is provided with a wedging surface 105 as illustrated.

I provide a block 106 from each side of which extends a trunnion 108, the block and trunnions constituting first trunnion means for the jaw 62. The arm members 90, 92 are mounted, respectively, on these trunnions 108 for rocking movement. The ends of the trunnions 108 extend, respectively, into the grooves 80 in the members 70, 72 and rollers 110 are journal mounted on the ends of the trunnions 108 to roll in the grooves 80. A sleeve-type piston rod 112 of the power means 66 extends downwardly through the cross bar 74 to have its distal end threadedly engaged in a vertically extending opening in the block 106as indicated at 114.

Each arm member 90, 92 also carries a trunnion 116 which extends outwardly into the adjacent groove 80 in the member 70, 72 and a roller 118 is journal mounted on that trunnion l 16 to roll in the groove, the trunnions 1 l6 constituting second trunnion means for the jaw 62. The grooves 80 have a rectangular cross section throughout their extent and the rollers 1 10, 116 have a similar but slightly smaller cross section so that the rollers can roll freely in the grooves.

The lower jaw 64 is provided by a pair of arm members 126, 128 which correspond to the arm members 90, 92 and which may be fastened together by cross bars and by fastening elements such as indicated at 130. A blade 132 having a wedge surface 133 as illustrated is fastened to the arm members 126, 128.

I provide a block 134 from each side of which extends a trunnion 138, the block 134 and trunnions 138 constituting first trunnion means for the jaw 64. The arms 126, 128 are journal mounted on these trunnions 138 for rocking movement. The outer end of each trunnion 138 extends into the adjacent groove 80 and a roller 140 is journal mounted on the outer end of each such trunnion. The rollers 140 correspond to the rollers 110 and roll, respectively, in the grooves 80 in the members 70, 72. A trunnion 142 extends outwardly from each member 126, 128 into the adjacent groove 80 and a roller 144 corresponding to the roller 118 is mounted on each trunnion 142 to roll in the adjacent groove 80, the trunnions 142.constituting second trunnion means for the jaw 64.

The block 134 is rigidly connected to the distal end of a piSton rod 136 by means such as the illustrated screw 137 which extends through the block to engage the piston rod as indicated at 137'. I

Thus, each jaw 62, 64 is rockable about its associated trunnion 110, 138 axis and movable vertically along the coinciding axes of the piston rods 112, 136 which are parallel to the intermediate portions of the grooves 80. In FIG. 3, the jaws 62, 64 are illustrated in solid lines in their respective releasing positions. The jaws 62, 64 move from their respective releasing positions to their respective gripping positions shown in broken lines in FIG. 3. In their releasing positions, the jaws 62, 64 are tilted rearwardly so that their blades 102, 132 are in a non-interference position relative to the knife and pressure bar assembly 46. The jaw 62 is moved to its rearwardly tilted position as the sleeve-type piston rod 112 is reciprocated upwardly and the rollers 118 move upwardly about the curved portions 84 of the grooves 80. Similarly, the jaw 64 is moved to its rearwardly tilted position when the piston rod 136 is reciprocated vertically downwardly and the rollers 144 move downwardly about the curved portions 82 of the grooves 80. When the jaws 62, 64 move into engagement with a flitch, they are moving vertically along the path defined by the axes of the piston rods .112, 136 and the straight intermediate portions of the grooves 80.

My illustrative power means 66 includes an upper hydraulic cylinder and a lower coaxially arranged hydraulic cylinder 152 as best seen in FIG. 4. I provide an upper end cap 154 closing the upper end of the upper cylinder 150, anintermediate cap 156 closing the lower end of the upper cylinder 150 and the upper end of the lower cylinder 152 and a lower end cap 158 closing the lower end of the lowercylinder. A piston 160 conventionally provided with a pair of peripherally extending sealing rings 162 reciprocates in the upper cylinder 150 with the piston rod 136 threadedly engaged therewith as indicated at 164. In the illustrative embodiment, the end cap 154 is provided with a peripherally extending slot 165 receiving the upper end of the cylinder 156 and a sealing ring 166 is disposed in the slot as illustrated. Similarly, the intermediate end cap 158 is provided with a peripherally extending a slot 167 receiving the lower end of the cylinder 150 and a sealing ring 168 is disposed in that slot as illustrated. A fluid access port 170 is provided in the end cap 154 and a port 172 is provided on the cap 156. A piston 174 having a pair of peripherally extending sealing rings 176 is axially shiftable in the lower cylinder 152 with the sleeve-type piston rod 112 engaged therewith as indicated at 178.

A fitting 182 is threadedly engaged in a concentric opening in the cross bar 74 asclearly seen in FIG. 4 with the eternal diameter of the fitting being provided with peripherally extending slots holding sealing rings 184 which engage the outer periphery of the rod 112. The fitting 182 provides a peripherally and upwardly extending sleeve portion 186 which extends into a bore 188 of the lower end cap1'58, the bore 188 being provided with a peripherally extending slot holding a sealing ring 190. engaging the outer diameter of the sleeve portion 186. The lower end of the cylinder 152 is received in a peripherally extending slot 194 in the end cap 158 and a peripherally extending sealingring 196 is disposed in that slot. The end cap 158 is provided with a port 198 through which hydraulic fluid is admitted to the lower cylinder 152.

When the pistons 160, 174 are in their positions illustrated in FIG. 4 and fluid is admitted under pressure to the port 172, the piston 160 and piston'rod 136 move vertically upwardly to move the jaw 64 from its lower, rearwardly tilted releasing position upwardly to its gripping position and the piston 174 and piston rod 1 12 move vertically downwardly to move the jaw 62 from its upper, rearwardly tilted releasing position downwardly to its gripping position.

The jaw 64 is returned to its lower, rearwardly tilted releasing position when hydraulic fluid under pressure is admitted to the cylinder 150 through the port 170 and the jaw 62 is returned to its upper, rearwardly tilted position when hydraulic fluid is admitted to the cylinder 152 through the port 198.

In FIG. 1, I show a control valve panel 200 which includes valves for -controlling the pistons 160, 174. The flow of hydraulic fluid through the cylinders 150, 152 may be controlled in a conventional manner which does not need to be described, in detail, herein.

jaws 62, 64 engage the flitches at a distance of, for instance, four inches from the mounting surface of the flitch table 16 while; the teeth portions 38 of the dogs 30, 32engage the 'flitch at a distance of, for instance, five-eighths inch from the mounting surface of the flitch table. Then, the slicing operation can begin and theslicing of the flitch can continue until the knife and pressure bar assembly'46 approach the jaws 62,64 at which time the jaws62, 64'are retracted to their perspective releasing positions leaving the flitch held by the dogs 30', 32. The, jaws 62, 64 can be retracted from their gripping positions to' their releasing positions without, in any manner, disturbing or halting the slicing operation. v r a.

The flitch table 16 is shown in its uppermost position in FIG. 1. When the flitch table'is in its uppermost position and the jaws 64 of the extension dog assemblies are in their lowermostposition, the jaws 64 are still below and out of the path of the knife and pressure bar assembly 46. Similarly, when the flitch table 16 is inits lowermost position and the jaws 62 of the assemblies 60 are in their releasing position, the jaws 62 are above and out of the path of the knife and pressure bar assembly 46. Particularly, the guiding means 68 and power means 66 are proportioned and designed such that, when the flitch table 16 reciprocates between its opposite positions mama jaws 62, 64 are in their respective releasing positions, the jaws donot cross the path of the knife and pressure hat assembly 46 as the knife 5 0. and pressure bar 52 advance toward the mounting surface of the flitch table.

Conventionally, a person, commonlycalled a veneer cutter, supervises the operation of a veneer slicer and operates its controls to stop the advancement of the knife and pressure bar assembly 46 as well as the reciprocation of the flitch table 16 if anything goes wrong and especially when the knife and presSure bar assembly approach the plane of movement of the dogs 30, 32. This person can operate the control panel 200 to move the jaws 62, 64 of the extension dog assemblies 60 to their respective releasing positions when the knife and pressure bar assembly 46 reaches a position relatively close to the plane of reciprocation of the blades 102, 132. This movement of the jaws 62, 64 to their releasing positions can be accomplished by admitting hydraulic fluid to the ports 170, 198 of the power means .66 of each extension dog assembly 60. This operation, of course, can be performed by operating a single valve or a pair or plurality of valves which are operated by a single lever or the like. Alternatively, a valve actuator, not shown, may be placed in a position to be operated by movement of the carriage 42 to a predetermined position relative to the plane of reciprocation of the blades 102, 132, thereby automatically to r the flitch securely against a central-portion of said.

retract the jaws 62, 64 to their releasing positions when the dogs 30, 32' while the flitch itself is gripped by the jaws 62, 64. After theflitch has been sliced down to the point where the knife and pressure bar assembly 46 is approaching the plane of reciprocation of the blades 102, 132, the jaws 62, 64 may be retracted to their releasing positions so that it is only. necessary for the glue between the flitch and the backing board to support a flitch which is, for instan e, Pptoximately four 1. In a veneer slicer comprising a flitch table provid-.

ing a mounting surface, dogs for gripping a flitch at a first distance from said mounting surface and holding mounting surface, and a knife and pressure bar assembly movablealong a path toward and away from said mounting surface, said flitch table being reciprocations and away from said central portion to theirreleas ing positions, power means for moving said opposing jaws between their respective gripping and releasing positions, said guiding meansand said power means being proportioned and designed such that, whensaid table reciprocates between said opposite positions and said jaws are in their respective releasing positions, said jaws will not interfere with said knife 'and'pressure bar assembly when it moves toward said mounting surface within the space defined by saidsecond distance.

: 2. The improvement of claim 1 in which each extension .dog assembly includes a rigid frame providing a pair of spaced apart and parallel elongated members having facing inner surfaces, said surfaces being provided with allochirally related longitudinally extending grooves providing said guiding means, said opposing jaws being received between said members, trunnion means extending outwardly from said jaws into said grooves, and roller means joumalled on each said trunnion means to roll in said grooves.

3. The improvement of claim 2 in which said flitch table reciprocates in a generally vertical plane and said frame is mounted on said flitch table to extend generally vertically, and in which said power means includes a lower generally vertically extending hydraulic cylinder mounted on said frame and an upperhydraulic cylinder coaxially mounted on said lower cylinder, a piston having a coaxially extending bore mounted for vertical reciprocation in said lower cylinder with a sleeve-type piston rod connected thereto to extend downwardly between said elongated members, a piston mounted for reciprocation in said upper cylinder with a second piston rod connected thereto to extend downwardly between said elongated members coaxially through said bore in said first-mentioned piston and said sleeve-type piston rod, said opposing jaws including a lower jaw connected to the distal end of said second piston rod and an upper jaw connected to the distal end of said sleeve-type piston rod.

4. The improvement of claim 3 in which each groove includes a straight vertically extending intermediate portion and an upper portion curved rearwardly away from said knife and pressure bar assembly and a lower portion curved rearwardly away from said knife and pressure bar assembly, said rearwardly curved portions defining said releasing positions respectively of said aws.

5. The invention of claim 4 in which said trunnion means includes, for each said jaw, a first horizontally extending trunnion means, the distal ends of which extend into said grooves and on which said jaw is mounted for rocking movement, and second horizontally extending trunnion means rigidly connected to said jaw and the distal ends of which extend into said grooves, the second trunnion means of said upper jaw being movable into said upper curved portions to tilt said upper jaw about is first trunnion means rearwardly to its releasing position and the second trunnion means of said lower jaw being movable into said lower curved portions to tilt said lower jaw about its first trunnion means rearwardly to its releasing position.

6. The invention of claim 5 in which the first trunnion means of said lower jaw if rigidly connected to the distal end of said second piston rod and the first trunnion means of said upper jaw is rigidly connected to the distal end of said sleeve-type piston rod.

7. The invention of claim 6 in which the second trunnion means of said upper jaw is disposed above its said first trunnion means and the second trunnion means of said lower jaw is disposed below its said first trunnion means.

8. The invention of claim 7 in which the coinciding axes of said piston rods are parallel to the intermediate portions of said grooves and in a common generally vertical plane with the axes of said first trunnion means.

9. The improvement of claim 1 in which each extension dog assembly includes a rigid frame providing a pair of spaced apart and parallel elongated guide members receiving therebetween and guiding said opposing jaws, in which said flitch table reciprocates in a generally vertical plane and said frame is mounted on said flitch table to extend generally vertically, and in which said power means includes a lower generally vertically extending hydraulic cylinder mounted on said frame and an upper hydraulic cylinder coaxially mounted on said lower cylinder, a piston having a coaxially extending bore mounted for vertical reciprocation in said lower cylinder with a sleeve-type piston rod connected thereto to extend downwardly between said elongated members, a piston mounted for reciprocation in said upper cylinder with a second piston rod connected thereto to extend downwardly between said elongated members coaxially through said bore in said first mentioned piston and said sleeve-type piston rod, said opposing jaws including a lower jaw connected to the distal end of said second piston rod and an upper jaw connected to the distal end of said sleeve-type piston rod.

10. The improvement of claim 2 in which said flitch able reci rocatesi a ene all ye cal lane and said irame rs mounted 0% said itc tab e to extend generally vertically and in which each groove includes a straight vertically extending intermediate portion and an upper portion curved rearwardly away from said knife and pressure bar assembly and a lower portion curved rearwardly away from said knife and pressure bar assembly, said rearwardly curved portions defining said releasing positions respectively of said jaws.

11. The improvement of claim 10 in which said opposing jaws include a lower jaw and an upper jaw, and in which said trunnion means includes, for each said jaw, a first horizontally extending trunnion means, the distal ends of which extend into said grooves and on which said jaw is mounted for rocking movement, and second horizontally extending trunnion means rigidly connected to said jaw and the distal ends of which extend into said grooves, the second trunnion means of said upper jaw being movable into said upper curved portions to tilt said upper jaw about its first trunnion means rearwardly to its releasing position and the second trunnion means of said lower jaw being movable into said lower curved portions to tilt said lower jaw about its first trunnion means rearwardly to its releasing position.

Po-ww "UNITED-STATES IP'ATEVNT OFFICE,

"CE'RTIFICATE'OFCORRECTION,

- I at0nt No. i 3 i v V Dated August 1 1972 InventO v Thomas F. Hale It is-certified-that.error-appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below: I

In the Abstract, line 25, "with""should-be within Column 1, line 49 after the Title, "extending'Yshould be extension I 7 Column 2, line 30, "potion'v' should be portion line 49, "a" (last occurrence) should be and I Column 4, line 49, "cured'. should be curved Column 6, line 22, delete "a"- (last occurrence); line 26, "on" should be in. line 33, "eternal" should be internal Column 7, line 16, "pershould be re'- line 64, "the" should be a I w Column 9 line 28 (Claim 6 line 2) "if" should be Signed and sealed this Zndday of January 1973.

(SEAL) Attest:

EDWARD M.,FLETCHER,JR. v ROBERT GOTTSCHALK Attesting Officer v I Commissioner of Patent 

1. In a veneer slicer comprising a flitch table providing a mounting surface, dogs for gripping a flitch at a first distance from said mounting surface and holding the flitch securely against a central portion of said mounting surface, and a knife and pressure bar assembly movable along a path toward and away from said mounting surface, said flitch table being reciprocable between first and second opposite positions transversely relative to the path of said knife and pressure bar assembly, the improvement comprising extension dog assemblies mounted on said flitch table and proportioned and designed to grip a flitch at a second and greater distance from said mounting surface, each extension dog assembly including opposing jaws positioned and designed to engage generally opposite portions of a flitch, means for guiding said jaws for movement toward said central portion to their gripping positions and away from said central portion to their releasing positions, power means for moving said opposing jaws between their respective gripping and releasing positions, said guiding means and said power means being proportioned and designed such that, when said table reciprocates between said opposite positions and said jaws are in their respective releasing positions, said jaws will not interfere with said knife and pressure bar assembly when it moves toward said mounting surface within the space defined by said second distance.
 2. The improvement of claim 1 in which each extension dog assembly includes a rigid frame providing a pair of spaced apart and parallel elongated members having facing inner surfaces, said surfaces being provided with allochirally related longitudinally extending grooves providing sAid guiding means, said opposing jaws being received between said members, trunnion means extending outwardly from said jaws into said grooves, and roller means journalled on each said trunnion means to roll in said grooves.
 3. The improvement of claim 2 in which said flitch table reciprocates in a generally vertical plane and said frame is mounted on said flitch table to extend generally vertically, and in which said power means includes a lower generally vertically extending hydraulic cylinder mounted on said frame and an upper hydraulic cylinder coaxially mounted on said lower cylinder, a piston having a coaxially extending bore mounted for vertical reciprocation in said lower cylinder with a sleeve-type piston rod connected thereto to extend downwardly between said elongated members, a piston mounted for reciprocation in said upper cylinder with a second piston rod connected thereto to extend downwardly between said elongated members coaxially through said bore in said first-mentioned piston and said sleeve-type piston rod, said opposing jaws including a lower jaw connected to the distal end of said second piston rod and an upper jaw connected to the distal end of said sleeve-type piston rod.
 4. The improvement of claim 3 in which each groove includes a straight vertically extending intermediate portion and an upper portion curved rearwardly away from said knife and pressure bar assembly and a lower portion curved rearwardly away from said knife and pressure bar assembly, said rearwardly curved portions defining said releasing positions respectively of said jaws.
 5. The invention of claim 4 in which said trunnion means includes, for each said jaw, a first horizontally extending trunnion means, the distal ends of which extend into said grooves and on which said jaw is mounted for rocking movement, and second horizontally extending trunnion means rigidly connected to said jaw and the distal ends of which extend into said grooves, the second trunnion means of said upper jaw being movable into said upper curved portions to tilt said upper jaw about is first trunnion means rearwardly to its releasing position and the second trunnion means of said lower jaw being movable into said lower curved portions to tilt said lower jaw about its first trunnion means rearwardly to its releasing position.
 6. The invention of claim 5 in which the first trunnion means of said lower jaw if rigidly connected to the distal end of said second piston rod and the first trunnion means of said upper jaw is rigidly connected to the distal end of said sleeve-type piston rod.
 7. The invention of claim 6 in which the second trunnion means of said upper jaw is disposed above its said first trunnion means and the second trunnion means of said lower jaw is disposed below its said first trunnion means.
 8. The invention of claim 7 in which the coinciding axes of said piston rods are parallel to the intermediate portions of said grooves and in a common generally vertical plane with the axes of said first trunnion means.
 9. The improvement of claim 1 in which each extension dog assembly includes a rigid frame providing a pair of spaced apart and parallel elongated guide members receiving therebetween and guiding said opposing jaws, in which said flitch table reciprocates in a generally vertical plane and said frame is mounted on said flitch table to extend generally vertically, and in which said power means includes a lower generally vertically extending hydraulic cylinder mounted on said frame and an upper hydraulic cylinder coaxially mounted on said lower cylinder, a piston having a coaxially extending bore mounted for vertical reciprocation in said lower cylinder with a sleeve-type piston rod connected thereto to extend downwardly between said elongated members, a piston mounted for reciprocation in said upper cylinder with a second piston rod connected thereto to extend downwardly between said elongated members coaxially through said bore in said first mentioned piston and said sleeve-Type piston rod, said opposing jaws including a lower jaw connected to the distal end of said second piston rod and an upper jaw connected to the distal end of said sleeve-type piston rod.
 10. The improvement of claim 2 in which said flitch table reciprocates in a generally vertical plane and said frame is mounted on said flitch table to extend generally vertically and in which each groove includes a straight vertically extending intermediate portion and an upper portion curved rearwardly away from said knife and pressure bar assembly and a lower portion curved rearwardly away from said knife and pressure bar assembly, said rearwardly curved portions defining said releasing positions respectively of said jaws.
 11. The improvement of claim 10 in which said opposing jaws include a lower jaw and an upper jaw, and in which said trunnion means includes, for each said jaw, a first horizontally extending trunnion means, the distal ends of which extend into said grooves and on which said jaw is mounted for rocking movement, and second horizontally extending trunnion means rigidly connected to said jaw and the distal ends of which extend into said grooves, the second trunnion means of said upper jaw being movable into said upper curved portions to tilt said upper jaw about its first trunnion means rearwardly to its releasing position and the second trunnion means of said lower jaw being movable into said lower curved portions to tilt said lower jaw about its first trunnion means rearwardly to its releasing position. 